Cobalt-coated cadmium sulfide photocatalytic hydrogen production material as well as preparation method and application thereof

Abstract

The invention provides a cobalt-coated cadmium sulfide photocatalytic hydrogen production material and a preparation method and application thereof, and relates to the technical field of photocatalytic materials.The preparation method of the cobalt-coated cadmium sulfide photocatalytic hydrogen production material specifically comprises the following steps that S1, thioacetamide and cadmium acetate dihydrate serve as raw materials, and CdS nanoparticles are prepared through a solvothermal method; s2, cobalt acetate tetrahydrate and the CdS nanoparticles prepared in the step S1 serve as raw materials, and the cobalt-coated cadmium sulfide photocatalytic hydrogen production material is prepared through an ion adsorption method. Compared with the prior art, the cobalt-coated cadmium sulfide photocatalytic hydrogen production material as well as the preparation method and the application thereof have the advantages that the autoxidation process of cadmium sulfide under the illumination condition is effectively inhibited, the dissolution of sulfur ions is reduced, the photochemical stability of the material is remarkably improved, and the service life of the material is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and in particular, to a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, a preparation method thereof, and an application thereof. Background Art

[0002] With the growth of global energy demand and the exacerbation of environmental problems brought about by fossil fuels, the development of clean and sustainable hydrogen energy technologies has become an important direction for solving the energy crisis. Photocatalytic water splitting for hydrogen production is a highly promising strategy that uses solar energy to drive water decomposition, directly converting light energy into chemical energy, and has the advantages of being green and low-cost. However, the key challenge of photocatalytic materials lies in how to simultaneously achieve efficient light absorption, rapid carrier separation, and stable surface reaction activity.

[0003] Cadmium sulfide (CdS), as a typical narrow-bandgap semiconductor (~2.4 eV), has been widely studied due to its excellent visible-light response ability. However, pure CdS has problems such as a high recombination rate of photo-generated electron-hole pairs and severe photocorrosion, resulting in limited photocatalytic activity and stability. In recent years, optimizing the performance of CdS through surface modification or heterostructure construction has become a research hotspot. Among them, transition metal cobalt (Co) is considered an ideal co-catalyst due to its rich valence states, good catalytic activity, and low-cost advantages. The introduction of cobalt elements (such as CoOx, CoP, or single-atom Co) can improve the performance of CdS through the following mechanisms: (1) acting as an electron acceptor to accelerate the transfer of photo-generated electrons from CdS to cobalt active sites, inhibiting carrier recombination; (2) regulating the surface energy band structure of CdS and optimizing the hydrogen evolution reaction (HER) kinetics; (3) forming a protective layer to reduce the photocorrosion of CdS. In addition, the synergistic effect between cobalt and CdS may further enhance the light absorption and charge separation efficiency by forming a Schottky junction or surface defect states.

[0004] Currently, the preparation methods of cobalt-modified CdS (such as chemical deposition, photodeposition, etc.) and their structure-activity relationships still need to be further explored. For example, the influence mechanisms of the cobalt loading amount, chemical state, and interface structure on the catalytic activity are not yet clear, and there is still room for improvement in the long-term cycle stability. Therefore, systematically studying the microstructure design, interfacial charge transport mechanism, and photocatalytic hydrogen production performance of cobalt-coated cadmium sulfide not only helps to deepen the understanding of the synergistic effect between semiconductors and co-catalysts but also provides theoretical and technical support for the development of efficient and stable photocatalytic hydrogen production materials. Summary of the Invention

[0005] To overcome the defects of the above prior art, the present invention provides a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, a preparation method thereof, and an application thereof, which effectively inhibits the self-oxidation process of cadmium sulfide under light conditions, reduces the dissolution of sulfide ions, significantly improves the photochemical stability of the material, and extends its service life.

[0006] The present invention provides a preparation method of a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, and the preparation method specifically includes the following steps: S1. Using thioacetamide and cadmium acetate dihydrate as raw materials, CdS nanoparticles are prepared by a solvothermal method; S2. Using cobalt(II) acetate tetrahydrate and the CdS nanoparticles prepared in step S1 as raw materials, a cobalt-coated cadmium sulfide photocatalytic hydrogen production material is prepared by an ion adsorption method.

[0007] Compared with the prior art, by adopting the above preparation method, cobalt ions are uniformly coated on the surface of cadmium sulfide (CdS) in the present invention, significantly improving the separation efficiency of photo-generated electron-hole pairs, reducing the carrier recombination rate, and thus greatly enhancing the photocatalytic hydrogen production activity; the introduction of cobalt as a co-catalyst effectively reduces the energy barrier of the hydrogen evolution reaction (HER), accelerates the surface reaction kinetics, and significantly increases the hydrogen production rate.

[0008] The cobalt coating layer not only enhances the visible light absorption range of cadmium sulfide, but also further improves the light energy utilization rate through the local surface plasmon resonance effect (LSPR), enabling the material to exhibit efficient photocatalytic performance in a wide spectral range; meanwhile, the cobalt coating layer effectively inhibits the self-oxidation process of cadmium sulfide under light irradiation, reduces the dissolution of sulfur ions, significantly improves the photochemical stability of the material, and extends its service life.

[0009] In a possible implementation manner, the specific steps of step S1 are as follows: Weigh thioacetamide and cadmium acetate dihydrate and place them in a container, sequentially add ethylene glycol, n-octanol and deionized water, stir and dissolve to obtain a mixed solution, keep the mixed solution under heat preservation reaction and then cool it to obtain a semi-finished product, and sequentially wash, centrifuge and dry the semi-finished product to obtain CdS nanoparticles.

[0010] Compared with the prior art, ethylene glycol, n-octanol and deionized water are further used as a solvent system in the present invention because these solvents can not only effectively dissolve the reactants, but also help to form a uniformly dispersed precursor solution, thereby promoting a more uniform nucleation and growth process and improving the quality of CdS nanoparticles; through steps such as washing, centrifuging and drying, unreacted raw materials and other impurities can be effectively removed to ensure the obtained CdS nanoparticles have high purity. At the same time, such treatment also helps to improve the dispersibility of the nanoparticles and reduce the agglomeration phenomenon, which is crucial for the subsequent cobalt coating step. In summary, due to their high quality and good dispersibility, the CdS nanoparticles prepared by the above method are more easily coated with cobalt uniformly in the subsequent steps, thereby achieving better separation efficiency of photo-generated electron-hole pairs, reducing the carrier recombination rate, and enhancing the photocatalytic hydrogen production activity.

[0011] In a possible implementation, in step S1, the mass ratio of thioacetamide to cadmium acetate dihydrate is 1:(1.5 - 2).

[0012] In a possible implementation, the parameters for the heat preservation reaction are as follows: the temperature is 175 - 185 °C, and the time is 3.5 - 4.5 h.

[0013] Compared with the prior art, the advantage of the present invention adopting the above parameters is that: this temperature range (175 - 185 °C) helps to promote the nucleation and crystal growth process of cadmium sulfide. Within this temperature range, it can ensure that the chemical reaction proceeds at a moderate rate, avoiding the influence of too fast or too slow reaction rates on the crystal quality. The appropriate temperature can provide sufficient energy to promote the effective collision and transformation between reactant molecules, thereby forming high-quality and uniform CdS nanostructures.

[0014] In a possible implementation, the parameters for the centrifugation are as follows: the rotation speed is 7500 - 8500 r / min, and the time is 8 - 12 min.

[0015] Compared with the prior art, by setting a relatively high rotation speed (7500 - 8500 revolutions per minute) in the present invention, sufficient centrifugal force can be generated in a short time to effectively separate CdS nanoparticles from impurities, unreacted precursors or other by-products in the solution.

[0016] In a possible implementation, the parameters for the drying are as follows: the temperature is 55 - 65 °C, and the time is 11 - 13 h.

[0017] Selecting a relatively low drying temperature (55 - 65 °C) can avoid thermal damage or crystal form transformation to CdS nanoparticles caused by high temperature. A relatively high temperature may lead to agglomeration of nanoparticles or an increase in crystal defects, thereby affecting their physical and chemical properties and the final photocatalytic performance. Although the drying temperature is relatively low, by extending the drying time to 11 - 13 hours, it ensures that water and other volatile substances can fully evaporate, enabling the sample to reach the required drying degree. The long-time gentle drying helps to reduce the residual solvent or water inside and on the surface of the particles, promoting a more uniform drying effect.

[0018] In a possible implementation, the specific steps of step S2 are as follows: Weigh the CdS nanoparticles prepared in step S1, add a cobalt acetate tetrahydrate solution, and continuously stir for an adsorption reaction; after the adsorption reaction ends, successively perform washing, centrifugation and drying treatments to obtain CdS@Co nanoparticles, and then perform heat treatment to obtain a cobalt-coated cadmium sulfide photocatalytic hydrogen production material.

[0019] The adsorption reaction is carried out by adding CdS nanoparticles to a cobalt acetate tetrahydrate solution and continuously stirring, which can ensure that cobalt ions are evenly adsorbed on the surface of CdS nanoparticles. As a cocatalyst, cobalt can effectively reduce the energy barrier of the hydrogen evolution reaction (HER), accelerate the surface reaction kinetics, and significantly improve the hydrogen production rate. At the same time, the cobalt coating layer enhances the visible light absorption range of cadmium sulfide and may further improve the light energy utilization efficiency through the local surface plasmon resonance effect (LSPR).

[0020] In a possible implementation, the mass ratio of the cobalt acetate tetrahydrate to the CdS nanoparticles is (5 - 7):1.

[0021] In a possible implementation, the stirring reaction time is 3 - 5 h.

[0022] In a possible implementation, the parameters of the centrifugation are as follows: the rotation speed is 7000 - 9000 r / min, and the time is 8 - 12 min.

[0023] In a possible implementation, the drying treatment is carried out in a vacuum, and the drying time is 10 - 12 h.

[0024] In a possible implementation, the specific steps of the heat treatment are as follows: put the CdS@Co nanoparticles into a magnetic boat and place it in a tubular furnace. After introducing argon into the tubular furnace for 30 - 40 min, heat it up to 170 - 190 °C and keep it warm for 1 - 3 h.

[0025] Introducing argon into the tubular furnace for 30 - 40 minutes ensures that the treatment process is carried out in an inert gas environment. This can effectively prevent the CdS@Co nanoparticles from undergoing unnecessary oxidation reactions or other side reactions with oxygen or moisture in the air during the heating process, thus maintaining the chemical stability of the material. Selecting a relatively low temperature range (170 - 190 °C) for the heat preservation treatment can promote the interaction between cobalt and CdS without damaging CdS and the cobalt coating layer, which helps to form a more stable core - shell structure. This mild heat treatment method avoids problems such as grain growth and reduction of surface active sites that may be caused by high temperatures, and is beneficial to maintaining or even improving the photocatalytic performance.

[0026] The second object of the present invention is to provide a cobalt - coated cadmium sulfide photocatalytic hydrogen - producing material prepared by the above - mentioned preparation method.

[0027] The third object of the present invention is to provide an application of a cobalt-coated cadmium sulfide photocatalytic hydrogen production material in the field of photocatalytic water splitting for hydrogen production. The specific steps of the application are as follows: Put the cobalt-coated cadmium sulfide photocatalytic hydrogen production material into a photocatalytic reactor, add water and lactic acid, then add a magnetic stir bar and turn on the photocatalytic reactor. During the reaction process, continuously stir and control the rotation speed at 500 r / min.

[0028] Compared with the prior art, the present invention has the following advantages by adopting the above preparation method: 1. Simple preparation process and low cost: The preparation method adopted by the present invention is easy to operate, the raw materials are easily available, and no complex equipment is required. It is suitable for large-scale production and has high economic efficiency and practicality.

[0029] 2. Environmentally friendly and highly sustainable: This material uses solar energy as the driving energy, and there are no pollutant emissions during the reaction process, which conforms to the concepts of green chemistry and sustainable development and has broad application prospects.

[0030] 3. Strong structural controllability: By adjusting the thickness, distribution and chemical state of the cobalt coating layer, the interfacial charge transfer performance and catalytic activity of the material can be further optimized to meet the requirements of different application scenarios.

[0031] 4. Multifunctionality: In addition to photocatalytic hydrogen production, this material can also be applied to fields such as photocatalytic CO2 reduction and organic pollutant degradation, and has broad multifunctionality. Description of the Drawings

[0032] Figure 1 UV-visible absorption spectra of CdS coated with different metal ions; Figure 2 Scanning electron microscope image of CdS@Co prepared in Example 1; Figure 3 High-resolution transmission electron microscope image of CdS@Co; Figure 4 Photocatalytic hydrogen production performance results of CdS samples and those coated with different metals; Figure 5 Cyclic stability test results of the photocatalytic hydrogen production performance of CdS@Co; Figure 6 Quantum yield results of the photocatalytic hydrogen production performance of CdS@Co samples under different monochromatic lights. Detailed Description of the Invention

[0033] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of specific embodiments of the present invention. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0034] It should be noted that the endpoints and any values within the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0035] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. In some cases, for the purpose of clarification or facilitating citation, terms with conventional meanings are defined herein. Such definitions herein should not be construed as indicating a significant difference from the conventional understanding in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments follows the protocols and parameters provided by the manufacturers.

[0036] Example 1 This example provides a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, which is prepared by the following method: S1. Preparation of CdS nanoparticles by solvothermal method: Weigh 0.6011 g of thioacetamide and 1.0661 g of cadmium acetate dihydrate and add them to a beaker. Then, add 20 ml of ethylene glycol, 10 ml of n-octanol, and 10 ml of deionized water to the beaker in sequence. After stirring until dissolved, transfer the solution in the beaker to a high-pressure reaction kettle and place it in an oven. Set the temperature to 180 °C and keep it warm for 4 h. After the insulation is completed, wait for the temperature of the reaction kettle to drop to room temperature. Then, centrifuge and wash the obtained CdS nanoparticles three times each with ethanol and deionized water, with a centrifuge speed of 8000 r / min and a time of 10 min. After vacuum drying the washed CdS nanoparticles at 60 °C for 12 h, grind and collect them for standby; S2. Adsorption and Coating of Cobalt Ions on CdS Nanoparticles: Weigh 0.6227 g of cobalt acetate tetrahydrate and place it in a beaker. Add 50 ml of deionized water to the beaker and stir until dissolved. Weigh 100 mg of the prepared CdS nanoparticles and slowly add them to the dissolved cobalt acetate tetrahydrate solution. Continuously stir for 4 h to allow them to fully adsorb Co ions. After stirring, centrifuge and wash 5 times with deionized water to remove the excess cobalt ions. The centrifuge speed is 8000 r / min and the time is 10 min. Vacuum dry the washed CdS@Co nanoparticles for 12 h, then grind and collect them. Place the CdS@Co nanoparticles in a magnetic boat and put it into a tubular furnace. After purging the tubular furnace with argon for 30 min, heat it up to 180 °C and hold for 2 h. Wait for the temperature to drop to room temperature and then grind and collect for standby;

[0037] S3. Photocatalytic Hydrogen Production from Water by CdS@Co Photocatalyst: Weigh 10 mg of the prepared CdS@Co nanoparticles and put them into a photocatalytic reactor. Add 30 ml of deionized water and 10 ml of lactic acid to the reactor. Add a magnetic stir bar and connect the reactor well. Continuously stir during the reaction at a speed of 500 r / min. Use an AM1.5G xenon lamp light source to simulate sunlight irradiating the reactor. Qualitatively and quantitatively analyze the gas products generated in the reaction by gas chromatography. Draw a hydrogen standard curve by the external standard method (R 2 > 0.999) and calculate the hydrogen production rate.

[0038] Example 2 This example provides a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, which is prepared by the following method: S1. Preparation of CdS Nanoparticles by Solvothermal Method: Weigh 0.6011 g of thioacetamide and 1.0661 g of cadmium acetate dihydrate and add them to a beaker. Add 20 ml of ethylene glycol, 10 ml of n-octanol and 10 ml of deionized water to the beaker in turn. After stirring until dissolved, transfer the solution in the beaker to a high-pressure reaction kettle and place it in an oven. Set the temperature to 180 °C and hold for 4 h. After the holding is completed, wait for the temperature of the reaction kettle to drop to room temperature. Then, centrifuge and wash the obtained CdS nanoparticles three times each with ethanol and deionized water. The centrifuge speed is 7500 r / min and the time is 8 min. Vacuum dry the washed CdS nanoparticles at 55 °C for 11 h, then grind and collect for standby; S2. Adsorbing and Coating CdS Nanoparticles with Cobalt Ions: Weigh 0.6227 g of cobalt acetate tetrahydrate and place it in a beaker. Add 50 ml of deionized water to the beaker and stir until dissolved. Weigh 100 mg of the prepared CdS nanoparticles and slowly add them to the dissolved cobalt acetate tetrahydrate solution. Continuously stir for 3 h to allow them to fully adsorb Co ions. After stirring, centrifuge and wash 5 times with deionized water to remove the excess cobalt ions. The centrifuge speed is 7000 r / min and the time is 8 min. Vacuum dry the washed CdS@Co nanoparticles for 12 h, then grind and collect them. Place the CdS@Co nanoparticles in a magnetic boat and put it into a tube furnace. After purging the tube furnace with argon for 30 min, heat it up to 170 °C and keep it warm for 1 h. Wait for the temperature to drop to room temperature, then grind and collect them for standby.

[0039] S3. Application of Photocatalyst CdS@Co in Photocatalytic Water Splitting for Hydrogen Production: Weigh 10 mg of the prepared CdS@Co nanoparticles and put them into a photocatalytic reactor. Add 30 ml of deionized water and 10 ml of lactic acid to the reactor. Add a magnetic stir bar and connect the reactor. Continuously stir during the reaction at a speed of 500 r / min. Use an AM1.5G xenon lamp light source to simulate sunlight irradiating the reactor. Qualitatively and quantitatively analyze the gas products generated in the reaction by gas chromatography. Draw a hydrogen standard curve (R 2 > 0.999) by the external standard method and calculate the hydrogen production rate.

[0040] Example 3 This example provides a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, which is prepared by the following method: S1. Preparation of CdS Nanoparticles by Solvothermal Method: Weigh 0.6011 g of thioacetamide and 1.0661 g of cadmium acetate dihydrate and add them to a beaker. Add 20 ml of ethylene glycol, 10 ml of n-octanol, and 10 ml of deionized water to the beaker in sequence. After stirring until dissolved, transfer the solution in the beaker to a high-pressure reaction kettle and put it into an oven. Set the temperature to 180 °C and keep it warm for 4 h. After the heat preservation is over, wait for the temperature of the reaction kettle to drop to room temperature. Then, centrifuge and wash the obtained CdS nanoparticles three times each with ethanol and deionized water. The centrifuge speed is 8500 r / min and the time is 12 min. Vacuum dry the washed CdS nanoparticles at 65 °C for 13 h, then grind and collect them for standby. S2. Adsorption and Coating of Cobalt Ions on CdS Nanoparticles: Weigh 0.6227 g of cobalt acetate tetrahydrate and place it in a beaker. Add 50 ml of deionized water to the beaker and stir until dissolved. Weigh 100 mg of the prepared CdS nanoparticles and slowly add them to the dissolved cobalt acetate tetrahydrate solution. Continuously stir for 5 h to allow sufficient adsorption of Co ions. After stirring, centrifuge and wash 5 times with deionized water to remove excess cobalt ions. The centrifugation speed is 9000 r / min and the time is 12 min. Vacuum dry the washed CdS@Co nanoparticles for 12 h, then grind and collect them. Place the CdS@Co nanoparticles in a magnetic boat and put them into a tube furnace. After purging the tube furnace with argon for 40 min, heat it to 190 °C and hold for 3 h. Wait for the temperature to drop to room temperature, then grind and collect for standby;

[0041] S3. Photocatalytic Hydrogen Production Application of Photocatalyst CdS@Co: Weigh 10 mg of the prepared CdS@Co nanoparticles and put them into a photocatalytic reactor. Add 30 ml of deionized water and 10 ml of lactic acid to the reactor. Add a magnetic stir bar and connect the reactor well. Continuously stir during the reaction at a speed of 500 r / min. Use an AM1.5G xenon lamp light source to simulate sunlight irradiation of the reactor. Qualitatively and quantitatively analyze the gas products generated in the reaction by gas chromatography. Draw a hydrogen standard curve (R 2 > 0.999) by the external standard method and calculate the hydrogen production rate.

[0042] Example 4 This example provides a nickel-coated cadmium sulfide photocatalytic hydrogen production material. The difference from Example 1 is only that the raw material in this example is replaced by nickel acetate instead of cobalt acetate, and the mass of nickel acetate in the raw material is 0.6221 g. Others are the same as in Example 1 and will not be elaborated here.

[0043] Example 5 This example provides a zinc-coated cadmium sulfide photocatalytic hydrogen production material. The difference from Example 1 is only that the raw material in this example is replaced by zinc acetate instead of cobalt acetate, and the mass of zinc acetate in the raw material is 0.5488 g. Others are the same as in Example 1 and will not be elaborated here.

[0044] Example 6 This example provides a copper-coated cadmium sulfide photocatalytic hydrogen production material. The difference from Example 1 is only that the raw material in this example is replaced by copper acetate instead of cobalt acetate, and the mass of copper acetate in the raw material is 0.4991 g. Others are the same as in Example 1 and will not be elaborated here.

[0045] Example 7 This embodiment provides a bismuth-coated cadmium sulfide photocatalytic hydrogen production material. The difference from Example 1 is only that the raw material in this embodiment is replaced with bismuth acetate instead of cobalt acetate, and the mass of bismuth acetate in the raw material is 0.9652 g. Others are the same as in Example 1 and will not be elaborated here.

[0046] Comparative Example 1 This comparative example provides a cadmium sulfide material.

[0047] The inventors detected the performance of the materials prepared in Examples 1 - 7 and Comparative Example 1, and the detection results are as Figures 1 - 5 shown, where Figure 1 is the UV-visible absorption spectrum of CdS coated with different metal ions; it can be seen from Figure 1 that CdS coated with different metal ions has absorption in the UV-visible light range. Among them, the sample coated with Co ions has a significantly enhanced light absorption intensity compared with pure CdS, which is beneficial to the utilization rate of light in the photocatalytic hydrogen production reaction and helps to improve the hydrogen production efficiency; Figure 2 is the scanning electron microscope image (SEM) of CdS@Co prepared in Example 1. It can be seen from Figure 2 that the microscopic morphology of the CdS@Co sample is irregular nanoparticles, approximately spherical and stacked with each other, and the size is about 30 - 50 nm; Figure 3 is the high-resolution transmission electron microscope image of CdS@Co. It can be seen from Figure 3 that obvious lattice fringes can be observed in the CdS@Co sample prepared in the present invention, proving that the sample has good crystallinity; Figure 4 is the photocatalytic hydrogen production performance result graph of the CdS sample and the samples coated with different metals. It can be seen from Figure 4 that within a hydrogen production test cycle of 120 min, the sample coated with Co ions shows a relatively high hydrogen production efficiency. The hydrogen production rate reaches 22.9 mmol / g at 120 min, and the performance improvement is very significant compared with pure CdS and other samples coated with different metals; Figure 5 is the test graph of the cyclic stability result of the photocatalytic hydrogen production performance of CdS@Co. It can be known from Figure 5 that in the hydrogen production performance test with a cycle of 2 h, the CdS@Co sample still maintains stable hydrogen production activity after 7 cycles; Figure 6 is the quantum yield result graph of the photocatalytic hydrogen production performance of the CdS@Co sample under different monochromatic lights. It can be known from Figure 6 that the CdS@Co sample shows the best quantum yield of 13.2% under the irradiation of monochromatic light at 450 nm. Comparing its absorption spectrum, it is more in line with the expected absorption intensity in the visible light region. As the absorption intensity gradually decreases, the quantum yield of the corresponding monochromatic light also gradually decreases.

[0048] As described above, it is only the specific implementation manner of the present application. However, the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for preparing a cobalt-coated cadmium sulfide photocatalytic hydrogen production material, characterized in that: The preparation method specifically comprises the following steps: S1, using thioacetamide and cadmium acetate dihydrate as raw materials, CdS nanoparticles were prepared by solvothermal method; S2. Using cobalt acetate tetrahydrate and the CdS nanoparticles obtained in step S1 as raw materials, a cobalt-coated cadmium sulfide photocatalytic hydrogen production material is prepared by an ion adsorption method.

2. The preparation method according to claim 1, characterized in that The specific steps of step S1 are as follows: weigh thioacetamide and cadmium acetate dihydrate and place them in a container, add ethylene glycol, n-octanol and deionized water in sequence, stir and dissolve to obtain a mixed solution, keep the mixed solution warm for reaction and then cool it to obtain a semi-finished product, and wash, centrifuge and dry the semi-finished product in sequence to obtain CdS nanoparticles.

3. The preparation method according to claim 2, characterized in that: In the step S1, the mass ratio of thioacetamide to cadmium acetate dihydrate is 1:(1.5-2); And / or, the parameters of the heat preservation reaction are as follows: temperature is 175-185° C., and time is 3.5-4.5 h.

4. The preparation method according to claim 2, characterized in that: The centrifugal parameters are as follows: speed 7500-8500r / min, time 8-12min; And / or, the drying parameters are as follows: temperature is 55-65°C, time is 11-13h.

5. The preparation method according to claim 1, characterized in that: The specific steps of step S2 are as follows: weigh the CdS nanoparticles obtained in step S1, add cobalt acetate tetrahydrate solution, and continue stirring to perform adsorption reaction; after the adsorption reaction is completed, wash, centrifuge and dry in sequence to obtain CdS@Co nanoparticles, and then perform heat treatment to obtain cobalt-coated cadmium sulfide photocatalytic hydrogen production material.

6. The preparation method according to claim 5, characterized in that: The mass ratio of the cobalt acetate tetrahydrate to the CdS nanoparticles is (5-7):1; And / or, the stirring reaction time is 3-5h.

7. The preparation method according to claim 5, characterized in that: The centrifugal parameters are as follows: speed 7000-9000r / min, time 8-12min; And / or, the drying process is carried out in a vacuum, and the drying time is 10-12 hours.

8. The preparation method according to claim 5, characterized in that: The specific steps of the heat treatment are: putting CdS@Co nanoparticles into a magnetic boat and placing it in a tube furnace, introducing argon gas into the tube furnace for 30-40 minutes, then raising the temperature to 170-190° C. and keeping the temperature for 1-3 hours.

9. A cobalt-coated cadmium sulfide photocatalytic hydrogen production material, characterized in that: The method is prepared by any one of claims 1 to 8.

10. An application of the cobalt-coated cadmium sulfide photocatalytic hydrogen production material according to claim 9 in the field of photocatalytic water hydrogen production, characterized in that: The specific steps of the application are as follows: placing the cobalt-coated cadmium sulfide photocatalytic hydrogen production material into a photocatalytic reactor, adding water and lactic acid, adding a magnetic stirrer and turning on the photocatalytic reactor, stirring continuously during the reaction, and controlling the rotation speed to 500r / min.

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